/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Reflection;

namespace Spring.Core;

/// <summary>
/// Criteria that is satisfied if the return <see cref="System.Type"/> of a given
/// <see cref="System.Reflection.MethodInfo"/> matches a given <see cref="System.Type"/>.
/// </summary>
/// <author>Rick Evans</author>
public class MethodReturnTypeCriteria : ICriteria
{
    /// <summary>
    /// The return <see cref="System.Type"/> to match against if no
    /// <see cref="System.Type"/> is provided explictly.
    /// </summary>
    private static readonly Type DefaultType = typeof(void);

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="MethodReturnTypeCriteria"/> class.
    /// </summary>
    public MethodReturnTypeCriteria()
        : this(DefaultType)
    {
    }

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="MethodReturnTypeCriteria"/> class.
    /// </summary>
    /// <param name="type">
    /// The <see cref="System.Type"/> that the return type of a given
    /// <see cref="System.Reflection.MethodInfo"/> must match in order to satisfy
    /// this criteria.
    /// </param>
    public MethodReturnTypeCriteria(Type type)
    {
        ReturnType = type;
    }

    /// <summary>
    /// The <see cref="System.Type"/> that the return type of a given
    /// <see cref="System.Reflection.MethodInfo"/> must match in order to satisfy
    /// this criteria.
    /// </summary>
    public Type ReturnType
    {
        get { return _type; }
        set { _type = value == null ? DefaultType : value; }
    }

    /// <summary>
    /// Does the supplied <paramref name="datum"/> satisfy the criteria encapsulated by
    /// this instance?
    /// </summary>
    /// <param name="datum">The datum to be checked by this criteria instance.</param>
    /// <returns>
    /// True if the supplied <paramref name="datum"/> satisfies the criteria encapsulated
    /// by this instance; false if not or the supplied <paramref name="datum"/> is null.
    /// </returns>
    public bool IsSatisfied(object datum)
    {
        bool satisfied = false;
        MethodInfo method = datum as MethodInfo;
        if (method != null)
        {
            satisfied = method.ReturnType.Equals(ReturnType);
        }

        return satisfied;
    }

    private Type _type;
}
